Penny asked me "Am staying at the Skol Apartments and want to know where the nearest bus stop is for me to get to San Pedro de Alcantará - a map would be very useful! - many thanks."
I wrote back to say " Penny, here is a map of where Skol Apartments are in Marbella.
From your Skol Apartment walk up to Avenida Ricardo Soriano which is the main street in Marbella, past the Parque de la Constitución on your right.
The bus stop you need is on the other side of the main road, just where you see the "o" at the end of the word Soriano. You can't cross the road at that point but there is a pedestrian crossing on the other side of the big intersection.
If you look at this list of bus stops between Marbella and Estepona you will see that yours is called the Old Portillo stop. This is where the old Portillo bus station was. There is no trace of the bus station now!
I hope that helps you and that you have a great visit.